Results indicate the Liberal Party's first-preference vote has halved since the last election in 2015, with an almost 30 per cent swing against it.

Liberal candidate Julia Ham is currently in second place behind independent Joe McGirr. The Labor Party's Dan Hayes is in third place.

"At the moment it appears that of the three candidates in this contest, the Liberals are currently the least likely to win," Green said.

The winner out of Mr Hayes and Dr McGirr will take a week to be determined until after Thursday when the first preference tally is finalised, but Green said it was "certain the Liberals have lost".

Currently, with 84 per cent of votes counted, independent Dr McGirr is in the lead on 25.6 per cent, followed by Liberal candidate Ms Ham on 25.1 per cent and then Country Labor's Mr Hayes on 23.8 per cent.

The result will come down to preferences but as NSW has an optional preferential voting system, how those preferences flow will be difficult to predict.

If preferences flow according to how-to vote cards, Dr McGirr could pick up a swag of preferences from fellow independent Paul Funnell, who secured 10.8 per cent of the primary vote.

However, Labor could benefit from the preferences of the 10 per cent of voters who voted for the Shooters, Fishers and Farmers Party.

Dr Joe McGirr ran as an independent in the by-election.(Source: joemcgirrnews)

Dr McGirr told reporters last night he was "delighted … with the result and the counting" so far.

"I feel very honoured. So far we are ahead of the primary votes. That is a big vote of confidence," he said.

The Liberal Party has held the safe Riverina seat for about six decades since winning it in a by-election in 1957, before it was vacated by disgraced MP Daryl Maguire.

The by-election was held against the backdrop of the recent federal leadership spill, combined with revelations Mr Maguire sought payment over a property deal.

Dr McGirr told the ABC one of the reasons he put his hand up to run was because there was no Nationals candidate, and Nationals supporters had been handing out campaign material on his behalf.

But he denied he would defect to the regional party if he won.

"I have been an independent, I am an independent, and I intend to continue as an independent," he said.

Earlier in the night, Ms Ham told supporters that based on early figures she was unlikely to win.

Voters looking for 'change'

Earlier in the day at the North Wagga Public School booth, the mood of voters was distinctly against the Government.

Ron Edwards from Oura said he changed the way he voted.

"Without telling you who I voted for, we definitely need a change," he said.

Mr Edwards added that the recent federal leadership spill also influenced his vote.

"It was a bit silly. I've always believed we should vote for our own prime minister, not the government."

Another voter, who did not want to be named, said he was out to ensure Wagga was no longer a safe seat.

"I generally vote to make a seat marginal so things will happen," he said.

"Then the money will flow, the interest will flow, different parties want to win it.

"I number them all because I like to know where my preferences are going."